Depositing a metal layer onto a wafer, also known as “electroplating” or “electrodeposition,” is often a critical step in manufacturing an integrated circuit or semiconductor device. Substrates that undergo electroplating processes include 300 mm wafers and 450 mm wafers. Copper is often plated onto semiconductor wafers for device wiring in integrated circuits.
Electroplating cells are used in electroplating processes to provide a plating solution where metal electrolytes deposit onto the wafer. An electroplating cell may have several components, including a chamber with walls, a wafer support, an anode region, a plating solution region, a membrane separating such regions, various inlets, and an plating solution collecting region where overflowed plating solution is collected to be filtered, recirculated, and reintroduced into the plating solution.
In modern wafer electroplating processing, the quality of the deposited metal layer on the wafer is a major concern. In electroplating processes, a uniform, defect-free wafer is desired, since defects on the deposited metal film such as pits, protrusions, or particles reduce wafer performance and frequently yield.